Method for epoxy application control overpresses

Abstract

A method for placing a resin layer or shim on a frame member uses an overpress. The overpress has an inner surface with protruding nubs. The operator places a bead of liquid resin on the inner surface of the overpress, then clamps the overpress to the frame member. The clamps force the nubs of the overpress into contact with the frame member and allows the nubs to define a clearance between the overpress and the frame member. The liquid resin spreads throughout the clearance and cures. After the resin has cured, the overpress is removed from the frame member, leaving a layer of cured resin bound to the frame member. This layer is then machined to a desired thickness.

1. A method for placing a resin layer on a selected surface of a metal frame member of an aircraft, the method comprising the steps of:
 (a) providing an overpress having an inner surface with a plurality of nubs protruding therefrom; 
 (b) placing liquid resin on one of the surfaces of the overpress or the frame member; then 
 (c) forcing the nubs of the overpress in contact with the selected surface of the frame member, causing the liquid resin to spread across the said one of the surfaces and allowing the nubs to define a clearance between the overpress and the frame member that fills with the liquid resin; then 
 (d) allowing the liquid resin to cure into a layer of cured resin that bonds to the frame member, then removing the overpress from the selected surface of the frame member and the layer of cured resin; and 
 (e) leaving the layer of cured resin bonded to the selected surface of the frame member, the layer of cured resin having hollow spaces where the nubs previously were located. 
 
     
     
       2. The method of  claim 1 , wherein step (c) comprises manually securing the overpress to the frame member with one or more clamps. 
     
     
       3. The method of  claim 1 , wherein step (a) further comprises forming the nubs so that the nubs are staggered in relation to each other along a length of the overpress such that a line between any two adjacent nubs is not parallel to any side of the overpress. 
     
     
       4. The method of  claim 3 , wherein step (a) further comprises forming the nubs whereby a length of the nubs is less than a width of the overpress. 
     
     
       5. The method of  claim 1 , wherein step (d) further comprises the step of applying a release agent coating on the overpress to facilitate removing the overpress from the layer of cured resin after the liquid resin has cured. 
     
     
       6. The method of  claim 1 , wherein step (a) further comprises the step of forming the overpress with a translucent material and step (b) further comprises the step of utilizing a liquid resin that is visible through the overpress. 
     
     
       7. The method of  claim 1 , further comprising the step of machining the layer of cured resin to a lesser thickness after removal of the overpress and while the layer of cured resin remains bonded to the frame member. 
     
     
       8. The method of  claim 1 , wherein step (a) further comprises the step of forming a guide member on a lateral edge of the overpress, the guide member protruding from the inner surface of the overpress, and wherein step (c) further comprises the step of abutting the guide member against an edge of the frame member. 
     
     
       9. The method of  claim 1 , comprising filling the hollow spaces in the layer of cured resin. 
     
     
       10. A method for placing a resin layer on a selected surface of a metal frame member of an aircraft, the method comprising the steps of:
 (a) providing an overpress having an inner surface and one or more lateral edges, the overpress further having a plurality of nubs protruding from the inner surface of the overpress, the nubs located at the lateral edges; 
 (b) placing liquid resin on the inner surface of the overpress; then 
 (c) forcing the nubs of the overpress in contact with the selected surface of the frame member by securing a plurality of clamps between the overpress and the frame member, the nubs defining a clearance between the overpress and the frame member; 
 (d) after the liquid resin has cured, removing the overpress from the selected surface of the frame member, thereby, leaving a layer of cured resin bonded to the selected surface of the frame member, the layer of cured resin having hollow spaces where the nubs were previously located; then 
 (e) filling the hollow spaces with a resin or an epoxy and machining the layer of cured resin while remaining bonded to the frame member. 
 
     
     
       11. The method of  claim 10 , wherein step (a) further comprises forming the nubs so that they are staggered in relation to each other along a length of the overpress such that a line between at least two nubs is not parallel to any side of the overpress. 
     
     
       12. The method of  claim 10 , wherein step (a) further comprises forming overpress of a flexible epoxy resin. 
     
     
       13. The method of  claim 10 , wherein step (a) further comprises the step of forming a plurality of indicators on an outer surface of the overpress, each of the indicators being located opposite one of the nubs; and step (c) comprises contacting one leg of each of the clamps to one of the indicators so as to exert a clamping force directly through each of the nubs against the frame member. 
     
     
       14. The method of  claim 10 , wherein step (a) further comprises the step of forming one or more pull tabs on the overpress and step (d) comprises grasping the pull tab to pull the overpress from the cured resin layer bonded to the frame member. 
     
     
       15. The method of  claim 10 , wherein step (a) further comprises the step of forming tapered edges on the nubs. 
     
     
       16. A method of attaching a composite skin to a metal frame member of an aircraft, the method comprising the steps of:
 (a) providing an overpress haying an inner surface with a plurality of nubs protruding therefrom at a uniform distance from the inner surface; 
 (b) placing a bead of liquid resin on the inner surface of the overpress between the nubs; then 
 (c) clamping the nubs of the overpress in contact with the selected surface of the frame member, the nubs defining a clearance between the overpress and the frame member into which the bead of liquid resin spreads; 
 (d) allowing the liquid resin to cure into a layer of cured resin with a thickness the same as the clearance, then removing the overpress from the selected surface of the frame member and the layer of cured resin, thereby leaving the layer of cured resin bonded to the selected surface of the frame member, the layer of cured resin having hollow spaces previously occupied by the nubs; 
 (e) filling the hollow spaces with a resin or epoxy, then machining the layer of cured resin to a lesser thickness while the layer of cured resin remains bonded to the frame member; then 
 (f) attaching the skin to the frame member of the aircraft, the layer of cured resin being between the skin and the frame member. 
 
     
     
       17. The method of  claim 16 , wherein step (a) further comprises forming the nubs whereby a length of the nubs is less than a width of the overpress. 
     
     
       18. The method of  claim 16 , wherein step (b) further comprises the step of applying a release agent to the inner surface of the overpress prior to applying the bead of liquid resin. 
     
     
       19. The method of  claim 16 , wherein step (a) further comprises the step of forming the overpress with a translucent material and step (b) further comprises the step of utilizing a liquid resin that is visible through the overpress. 
     
     
       20. The method of  claim 16 , further comprising forming the overpress of a flexible material.